Conducting Subsurface Environmental Investigations in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 154

A΄
Southeast
0

A
Northwest Building

BLDG

0

15 15

30 30

Fine to medium-grained sand

Groundwater
flow direction

45 45

60 60

Monitoring well screens

75 75

Very fine-grained sand

90 90

Clay

105 105

420 360 300 240

(Meters)

160 120 60 0

FIGURE 4.24
Cross section showing multiple monitoring wells, horizontally and vertically (in m).

4.3.2.2 Groundwater Sampling

Collecting groundwater samples consists of a process involving the following nine steps
(modified from Harter 2003):

1. Preparation

2. Inspecting and accessing the monitoring well

3. Measuring the water level

4. Purging the well

5. Letting the well recover

6. Measuring the water level

7. Collecting the water sample

8. Decontamination

9. Securing the well after sampling

The preparation step involves the following:

• Establishing the list of parameters for analysis.
• Ensuring the purging and sample collection equipment including bailers and
pumps are in working order; these items should be new or properly decontaminated.
• Verifying the correct type and quantity of gloves, splash protection, and other
potentially required health and safety equipment are working properly; these
items should be new or properly decontaminated.